The invention relates generally to intelligent telecommunications networks (xe2x80x9cINsxe2x80x9d) and, more particularly, to a service control point (xe2x80x9cSCPxe2x80x9d) location register function for use in such INs.
The European Telecommunications Standardization Institute (xe2x80x9cETSIxe2x80x9d) and the International Telecommunications Union (xe2x80x9cITUxe2x80x9d) have developed a definition of the essential capabilities needed to support the deployment of intelligent telecommunications network (xe2x80x9cINxe2x80x9d) services. The first version of this xe2x80x9ccapabilities setxe2x80x9d (xe2x80x9cCS-1xe2x80x9d) was released in March, 1992, with a revised version (xe2x80x9cCS-1Rxe2x80x9d) released in May, 1995.
In an IN, during call processing, a Service Switching Point (xe2x80x9cSSPxe2x80x9d), such as a Mobile Switching Center (xe2x80x9cMSCxe2x80x9d), for example, launches queries to a Service Control Point (xe2x80x9cSCPxe2x80x9d) responsive to trigger Detection Points (xe2x80x9cDPsxe2x80x9d) defined by the CS-1R call model. The queried SCP responds with commands and data for processing the call-in-progress. The Transaction Capabilities Application Protocol, or xe2x80x9cTCAPxe2x80x9d, defines standard formats for the various query and response messages between the SSPs and the SCPs. Each query and response message includes data fields for containing a variety of pieces of information relating to the current call. For example, a TCAP query will include inter alia calling party number and called party number information, while a TCAP response will include inter alia call routing information. A DP represents a point in call processing at which an SSP can launch a query to an SCP to invoke IN service logic processing when the necessary criteria has been met.
There are many different DPs defined in the CS-1R call model. For example, DP2 is detected upon call origination; accordingly, xe2x80x9cDP2 Origination Trafficxe2x80x9d will be used herein to refer to call originations. DP12 is detected upon call termination; accordingly, xe2x80x9cDP12 Termination Trafficxe2x80x9d will be used herein to refer to call terminations. DP3 is detected based on specific set dialed digits, as defined in the SCP. If a caller places a call to that specific set of digits, DP3 is detected. The normal use of this DP is to detect calls to special numbers, such as 1-800 numbers, and trigger a dialog with the SCP to deal with them.
It is common for a wireless communications service provider to provide mobile subscribers with a telephone number, often a xe2x80x9c1-800xe2x80x9d number, to query an Account Management Service (xe2x80x9cAMSxe2x80x9d) regarding certain details of the subscriber""s account. In a multi-SCP IN architecture, such AMS queries (hereinafter xe2x80x9cDP3 AMS Trafficxe2x80x9d) present a unique problem when made using a wireline telephone, rather than the subscriber""s mobile unit. In particular, at the time of the call, the Mobile Subscriber""s Integrated Services Directory Number (xe2x80x9cMSISDNxe2x80x9d) of the subscriber is not known, so it is not possible to insure that the call initially is routed to the correct servicing SCP. However, the AMS must be executed by an SCP to prompt for and collect the subscriber""s MSISDN, thereby requiring that the call be assigned to an SCP. This presents an interesting catch-22, in that once the MSISDN is collected, it may turn out that the SCP executing the AMS is not the SCP to which the IN is directing traffic for the subscriber identified by the MSISDN.
Other potentially problematic situations encountered in connection with multi-SCP IN architecture arise in the context of a national roaming overlay network. In particular, in a national roaming overlay network, all overlay origination traffic (hereinafter xe2x80x9cNational Roaming DP2, DP3 Origination Trafficxe2x80x9d), including both IN and non-IN traffic, is routed from a visited network into a home network over one or more trunk groups. The traffic is routed without any additional IN processing in the visited network. This presents a problem in connection with IN traffic, which must be routed to a particular serving SCP, as there is no way to know to which SCP the traffic is to be routed, as well as non-IN traffic, which must simply be allowed to pass through with no additional IN processing in the home network.
Therefore, what is needed is a system for redirecting AMS queries, especially those made via wireline, and National Roaming DP2, DP3 Origination Traffic to the correct SCP in a multi-SCP IN architecture.
Accordingly, an SCP Location Register service (xe2x80x9cSLR servicexe2x80x9d) for redirecting certain DP2 and DP3 AMS Traffic to the appropriate SCP in a multi-SCP IN architecture is disclosed herein. In a preferred embodiment, the SLR service of the present invention is implemented on one or more SCPs in an IN comprising multiple SCPs.
In one aspect, the SLR service redirects DP3 AMS Traffic to the correct SCP without prompting twice for the MSISDN of interest. In this aspect, the network Global Title (xe2x80x9cGTxe2x80x9d) published for AMS access (e.g., xe2x80x9c1-800-Account-Managementxe2x80x9d) is provisioned to trigger the SLR service instead of the AMS, as would typically be the case. In particular, when a subscriber dials the AMS access GT, the Mobile Switching Center (xe2x80x9cMSCxe2x80x9d) triggers DP3, which in turn triggers InitDP to the SLR service.
Upon invocation, the SLR service looks up the called number in a Supported GT Translation (xe2x80x9cGTTxe2x80x9d) table. If the called number is located, the SLR service prompts for and collects the MSISDN of the subscriber of interest. The SLR service then performs a lookup of the MSISDN in an SLR Subscriber table, extracts the address of the serving SCP from the SLR Subscriber table entry corresponding to the MSISDN, and looks up this information in an SCP Address Mapping table. The SLR service extracts an SCP Access Code (xe2x80x9cSACxe2x80x9d) of the serving SCP from the SCP Address Mapping table and prepares and returns to the requesting MSC a CONNECT message in which the SAC is prepended to the original called number. The MSISDN is placed in a Redirecting Party ID field of the CONNECT message and the original calling number is left as is. The MSC triggers on the SAC and routes the query to the SCP indicated by the SAC, which processes the AMS query without reprompting for the subscriber""s MSISDN.
In another aspect, the SLR service supports redirection of National Roaming DP2, DP3 Origination Traffic. In this aspect, in the case of DP2 Origination Traffic, the caller""s MSISDN is present in a Calling Number field of the incoming message. Execution of the SLR service is similar to that described above for DP3 AMS query redirection. In particular, the SLR service attempts to look up the called number in the Supported GTT table. If the number is not present, the service assumes that it has been invoked for redirection of DP2 Origination traffic. If this is the case, the calling number is a valid subscriber MSISDN; hence, the SLR service need not prompt for and/or collect the MSISDN.
As described above, the SLR service then performs a lookup of the MSISDN in the SLR Subscriber table. In the case of IN traffic, the MSISDN will be found in the SLR Subscriber table and the SLR service extracts the address of the serving SCP from the SLR Subscriber table entry and looks up this information in an SCP Address Mapping table. The SLR service extracts an SCP Access Code (xe2x80x9cSACxe2x80x9d) of the serving SCP from the SCP Address Mapping table. Finally, the SLR service prepares and returns to the requesting MSC a CONNECT message in which the SAC is prepended to the original called number. The MSISDN is placed in a Redirecting Party ID field of the CONNECT message and the original calling number is left as is.
In the case of non-IN traffic, the MSISDN will not be located in the SLR Subscriber table and the SLR will respond to the requesting MSC with a CONTINUE (allowing the presented call to continue with no further IN processing) or ABORT (causing the presented call to be terminated) message, rather than a CONNECT message.
A technical advantage achieved with the invention is that wireline access to an AMS in a multi-SCP network architecture can be directed to the correct SCP without twice prompting for the MSISDN of the subscriber of interest.
Another technical advantage achieved with the invention is that National Roaming Overlay traffic in a multi-SCP network architecture can be routed to the correct SCP, in the case of IN traffic, or allowed to pass through, in the case of non-IN traffic.